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1981 CX500C
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Discussion Starter · #1 ·
So I swapped out my 81 CX500C forks with a set from a 83 GL650 interstate. I challenged myself in this build to try to use existing parts in most cases. But the new triple tree had no key switch mount like the CX500 forks, so I decided to move my key switch to underneath my tank on the right side. This left me with a handlebar clamp with a empty switch hole, which looked funny. One possible solution was to grind the switch mount completely off, but I thought that would look funny too. So my solution was to construct a small metal disc with carefully drilled holes and basically create a turn signal, neutral, high beam and oil pressure light using tiny LEDs from Ebay to replace the clunky idiot light box that sits between the speedo and tach on a stock bike. After drilling the holes, I welded a couple of machine screws to the backside of the plate and crafted a backing plate to bolt the whole assembly firmly within the key switch mounting ring, painted it with three coats of caliper paint, baked it off, then installed it as shown. Once I installed the light cluster I realized the stock mount for the instrument cluster had the speedo and tach way to far apart without the box between them, so I had to modify the stock instrument cluster mounts to move them closer together. Unfortunately, this picture shows my crappy welds on the mounting plate between the instruments. I guess I need to pull it all off, grind it down better, and re-paint, but it's really less noticeable than in the photo. Also forgive the layer of grinding dust in this pic. Anyway, I did this with my limited set of shop tools...a bench grinder, angle grinder and drill press. I think it manages to give a custom look while retaining a lot of the original elements. View attachment 210782
 

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Have you had a chance to "test" it in sunlight...?..
Those LEDs should last you longer than the globes.....us std (500) owners have to dissect the front to get to those lil buggars,,,
 

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1982 CX500C
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Have you had a chance to "test" it in sunlight...?..
Those LEDs should last you longer than the globes.....us std (500) owners have to dissect the front to get to those lil buggars,,,
I definitely am interested in the sun question too. This reminds me of the beautiful build from CXResurrection that I've been reading through lately: CX500 Monoshock and Frame/Seat Mod
 

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1981 CX500C
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Discussion Starter · #6 ·
I took the bike out on an overcast day (there hasn't been much direct sun for a couple of weeks here in the pacific northwest) and I didn't notice any trouble seeing seeing them. But I wasn't specifically looking to evaluate their dimness/brightness. I will try again when there is some sun out (probably around March of 2022, hehehe...).
That being said, they seemed surprisingly bright when I first tested them. Hopefully they perform OK in the sun, I hadn't really considered they might be too dim.

In other news, I do get a tiny bit of background green neutral light "spill over" when the bike is in gear, but it's not noticeable outdoors. There seems to be some stray current in the circuit that isn't enough to light a stock incandescent bulb. I also had to replace the flasher, of course, with a LED compatible unit.
 

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'84 CX650E that is evolving into a GL500
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You shouldn't have needed to change the flasher unless you changed the turn signals to LEDs too. If the signals are incandescent they should draw enough current for the original type flasher without the instrument panel bulbs.
That said, when I first put LED turn signals on my winter bike the (non original) flasher I had on it at the time worked OK until I replaced the instrument panel and used LEDs for indicators in it. It seems the little bulbs in the original panel were just enough to make the flasher work.

Many years ago I removed the tach from my GS400 and mounted the speedo in the middle, which meant that the light panel had to go. I still wanted to have the lights so I added a few wires to the handlebar switches so I could mount LEDs in them. You didn't notice them unless they were on and it worked well except that I sometimes didn't notice that the turn signals were still on unless I happened to glance at the handlebar and see the LED flashing.
I like your setup better.

Re brightness: I've had LED instrument panel lights on my bikes for years (some I provided myself, others that are in the Danmoto instruments) and I've had more concerns about them being too bright at night than not being bright enough in the daytime.
This is espcially true for newer LEDs that are much more efficient than ones made even 3 or 4 years ago. In fact, in the last year I changed both bikes to sequential turn signals that don't require a flasher and changed to green self flashing LEDs for the indicators; I have 6.2K ohm resistors in series with them (theoretically 1.9 mA - I don't have a meter that measures that low to confirm it) and they are more than bright enough in strong sunlight.

BTW: When I started using LED indicators on Eccles I initially had a high failure rate. I was also learning about using LEDs in model trains at the time and learned about protecting them from reverse voltage spikes by using a reverse biased LED. I have no idea where reverse spikes could come from on a bike but I don't think I've had any LEDs fail on a bike since I started using the circuit below. I wouldn't rush to pull yours apart to add the reverse diodes but in case any of them fail it might be a good idea to add the diodes when you replace them.

Font Parallel Rectangle Diagram Circle
 

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Is it standard practice for a reverse polarity diode in the circuit?
 

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'84 CX650E that is evolving into a GL500
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The diode is there to protect the LED from reverse voltage spikes. It does that by limiting the reverse voltage across the LED to whatever the diode's junction voltage is (less than 1V) and it needs to be connected in reverse polarity to the LED to do that.
As I said, I have no idea where reverse spikes would come from on a bike but since I started adding the protection diodes the only failures I've had were a couple on Eccles that were due to the LEDs' steel leads rusting (I have no idea why but they all have steel leads), which is much less likely on a bike that isn't used in the road salt season.
FWIW, I buy 1N4XXX series diodes 100 at a time on Bay for a few cents each so it is a cheap way to protect the LEDs.
 

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Should add....the impetus for the "sun question"....(not a criticism of your design)
My bike is a std500 without a "fly-screen" when bought....when I fitted an aftermarket fly-screen on it, the sunlight would refract through the screen and give me a "flash of the oil-pressure light" usually on wooded "canyon" roads...was unsettling the first few times...fixed by positioning my head lower forward....

In the sun you may find you need a small shield (aluminium/plastic) around your cluster you could test the design via just starting with cardboard or a cut down plastic cup taped in postion.... anyway just a thought.
 

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1981 CX500C
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Discussion Starter · #11 ·
Bahn, no worries, I am here to learn from everyones experiences and share my own humble ones. It will be interesting to see how all of my mods work once I actually get out on the road.
Thanks to Sidecar Bob as well for the great info on LEDs.
 

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'84 CX650E that is evolving into a GL500
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I find it more of a problem when the sun is low in the sky (like when I went out this afternoon) and it shines over my shoulder and I can't see the lights for the glare.
I had to relocate the LED voltmeter in Eccles' fairing because of that.
 
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